In a disc brake apparatus of such a type described in, for example, Patent Document 1 mentioned below, the brake pads are supported by the caliper in such a manner as to be movable in the axial direction of the disc rotor, by means of a single radially inner support shaft provided unitarily with the caliper and engaged with radially inner engagement surfaces of the back plates provided at positions corresponding to radially inner, circumferentially central portions of the linings with respect to the radial and circumferential directions of the disc rotor, and a single radially outer support shaft provided unitarily with the caliper and extending through the through holes of the back plates' arms extending radially outward with respect to the radial direction of the disc rotor and located toward the leading side of the linings; and the brake pads are supported by the caliper in such a manner as to be movable in the axial direction of the disc rotor, by means of torque reception surfaces (planes) formed on the caliper and engaged with respective end surfaces (planes) formed on the back plates and located toward the trailing side of the linings.